A framework for a dental prosthesis as shown in FIG. 4 is a unified metal or ceramic base structure consisting of a horizontal beam on which vertical posts, specific to the teeth they support are rigidly connected. This framework can be supported by dental implants placed in the jawbone. Such a framework is securely fixed to the jaw by screwing or cementing it onto the implants. The framework supports the specifically designed replacement teeth which are fused to the posts of the framework with a luting cement. The prosthesis containing this framework is patient-specific and must meet the strict requirements of accuracy to reach an optimal fit at the prosthesis/implant interface to distribute chewing and grinding forces appropriately to the underlying jawbone and avoiding high stresses to the underlying bone which could cause implants to deintegrate from the bone. The fit of the framework to the supporting implants should be 50 microns or less. Because the framework is capable of replacing all the teeth in a dental arch, and because the framework connects the occlusal surfaces of the replacement teeth to the osseointegrated dental implants, the dimensions of the framework are generally larger in comparison to traditional dental prostheses like crowns and tooth-supported bridges. The framework is designed to support not only replacement teeth but also the bone and gum tissue that previously immediately surrounded the missing teeth.
The traditional or conventional dental laboratory method for creating these frameworks is based on the manual design of a physical model of the framework in wax or resin and the production of the framework by means of lost wax casting or copy milling. These previous methods of framework production can be highly precise however they require very skilled dental laboratory technicians doing time-consuming modeling of the frame, a process that is inefficient and costly. The traditional lost wax process is very lengthy and highly labor intensive, consisting of many manual steps that include the design, manual contour and fabrication of the wax pattern, investing the pattern in a refractory mold, melting and evaporating the wax pattern in a high temperature burn out oven over many hours, melting the metal and casting it into the pattern mold, devesting the solidified metal framework and refining the surface of the framework to permit the next phase to begin. A current alternative to the lost wax casting method of framework construction is the use of CAD/CAM technology to scan the wax or resin pattern frame and robotically mill a precise copy of the pattern. Framework production by virtual technology is available but its ability to create tooth support mechanisms is limited.
Following completion of the metal or ceramic framework, impressions of that framework are made and stone casts are produced to replicate the metal framework. These casts are then cut into sections providing individual stone dies being replicas of the vertical tooth support portion of the framework pattern, upon which individual teeth are manually created from wax relying on the artistic skill of the dental technician. These individual teeth may then be either scanned or copy milled in a tooth colored material. These steps of custom fabrication of the individual prosthetic teeth are eliminated by the present invention thus avoiding time-consuming and highly skilled labor required of the dental technicians and ceramists. Furthermore, later if a tooth needs to be replaced because it has become worn or chipped, the above-described process must be repeated to provide a replacement for that tooth.
There is therefore a need in the dental arts for a method of prosthesis production which is less time-consuming and labor-intensive and which requires less skill. Further, there is a need for such a system which can also provide the highest quality result for the patient.